Traditional risk factor epidemiology has contributed to many public health breakthroughs revealing notable associations such as cigarette smoking and lung cancer. Recently, however, it has been challenged to further development. Some have suggested its methods are too imprecise to disentangle more subtle associations. Others have called for new paradigm shifts that consider not only individual risk factors but also factors at other levels as small as genes and as large as community and society. Training in other approaches is crucial in facing these challenges. This career development award will enable me to combine my training in traditional cancer epidemiologic methods with complementary expertise in other areas. My goal is to become an independent cancer epidemiologist who tackles research questions using a life course perspective. Five areas of training are proposed: recruitment and retention in urban populations, molecular epidemiology, perinatal epidemiology, advanced statistical methods, and ethics. My training in these areas will be supervised by four mentors -- Ezra Susser, M.D., Dr.P.H., Geoffrey Howe, Ph.D., Ruby Senie, Ph.D., and Regina Santella, Ph.D. The training objectives are directly related to my proposed research, which focuses on early determinants of breast cancer risk. My research projects will contribute to the existing literature in two main ways: 1) By developing refined and novel approaches of studying the influence of early life factors such as birthweight and preeclampsia; and 2) By investigating how these factors interact with childhood and adolescent factors in determining breast cancer risk. Newly collected data will enhance three ongoing studies: The Metropolitan New York Registry of Breast Cancer Families, the New York site of the National Collaborative Perinatal Project (NCPP), and the Early Determinants of Adult Health (EDAH) cohort. Extending the framework with which to view adult epithelial tumors like breast cancer to include the in utero period will promote a more thorough investigation of various stages along the life course as well as a more thoughtful integration of cancer risk factors with other disease processes.